Having jumped from support slots in sweaty clubs to headlining for thousands in theaters and arenas, bands like the Killers, Fall Out Boy and Panic! at the Disco know a thing or two about paying their dues before becoming box-office sellouts.

While factors like airplay, record sales, media buzz and Internet and TV exposure contributed to the leap, there was one common thread each band shared. "They all did their time as opening acts and took it one step at a time on a touring level," says Adam Zacks, a senior talent buyer at House of Blues Concerts in Seattle, who has worked with all three acts.

"When the Killers were in 500-seaters, they could've been in 1,000-seaters, and when they were playing 1,000-seaters, it could've been 2,000-seaters," says William Morris Agency's Kirk Sommer, who books the band. "But [bands] need time to mature in the proper environment. You can't do too much too soon."

Staying put in smaller venues can also create more buzz, which could lead to higher demand. This was the case with Fall Out Boy, Bob McLynn of Crush Management says. "We realized with Fall Out Boy that we could have sometimes played larger venues, but the goal was to keep playing these markets for years to come," McLynn says. "Our shows always sold out in advance and made it a hotter ticket next time the band came to town to a different, larger venue."

"Bands are developing really fast now," says Rich Best, VP of booking for Southern California at Live Nation. "Panic! at the Disco is a great example. Here's a band that was an opening act for Fall Out Boy on their theater tour. But when they came into it, they already had an underground following. Now, a year later, we sold out 12,000 tickets at the Long Beach Arena [on Dec. 6]."

Another crucial factor that could potentially carry an act into larger venues is a slot on a major festival, Vans Warped tour and Taste of Chaos founder Kevin Lyman says. "Any band that has been on the Warped tour has become worth more tickets. And a lot of them will step up to the mid-level," he says.

Here's a look at four touring acts that could jump into larger venues in 2007. The list was compiled based on the predictions of several talent buyers across the United States.

Label: Decaydance/Fueled by Ramen
Agent: Nick Storch, the Agency Group

With the MySpace-inspired track "New Friend Request," New York's Gym Class Heroes are reaching out to their more than 250,000 "friends" to make the jump into bigger venues in 2007. And if record sales are any indicator, GCH shouldn't have anything to worry about. The band's latest effort, "As Cruel As School Children," which dropped in July 2006, has sold 98,000 units in the United States -- 40,000 more than 2005's "The Papercut Chronicles," according to Nielsen SoundScan. Since day one, the band's formula for success has been simple. "It's basically Internet and touring," says Scott Nagelberg, who manages the group with McLynn of Crush Management. "It's not about putting a lot of money behind them. It's about building core fans who will come back and see them every time they play." GCH recently completed its first headlining tour of 500-capacity clubs, and now it's time for phase two. In mid-February through early April, the band -- which melds rap, punk and R&B -- will play up to 1,200-capacity venues. "If they tour correctly, they can cross over and play for hip-hop, punk or rock audiences," Lyman says. "They played on the Warped tour and totally won over the punk kids." Nagelberg says the band already has its fair share of hip-hop fans, along with an interesting combination of "15-year-old girls who weigh 70 pounds and six-foot-five, 300-pound guys."

Label: Teleprompt/Warner Bros.
Agents: Bryan Myers and Tim Beeding, Creative Artists Agency

Since its first club tour in 2005, New Orleans electro-rock outfit Mute Math has seen steady growth in all territories it visits, according to manager Kevin Kookogey of Teleprompt, which serves as a label and management company. "The markets where we started with 100 people, we're now doing 500, and the ones where we started with 200-500, we're now doing 1,000," Kookogey says. "Our average [venue capacity] by the end of 2007 will be about 1,000." Although Mute Math doesn't classify its music as Christian, the band received buzz in the summer of 2005 after a string of Christian festivals. More recently, Kookogey says a performance at Lollapalooza in 2006 and several appearances on late-night TV talk shows have helped build the band's name. Amy Corbin, a talent buyer with Charles Attal Presents, says the band plays larger rooms each time it visits the Texas market. "They've been steadily developing over the last couple years," Corbin says. "They have a really core fan base." Mute Math is supporting the Fray through the end of January before visiting Europe for a headline club tour. In March and April, the band returns to the States for another headlining tour, which includes a stop at Austin's South by Southwest. A new album can be expected in second-quarter 2008, according to Kookogey.

Label: Atlantic Records
Agent: Kirk Sommer, William Morris Agency

As U.K.-based Paolo Nutini prepares for his touring debut in the United States later this month, the soul-influenced musician already has offers to play "most of the big festivals in America" in 2007, according to his manager Mike Luba of Madison House. Days before the Jan. 30 release of his full-length debut, "These Streets," Nutini will play 200- to 500-seat clubs stateside before returning to the United Kingdom for more shows in April. And by the end of 2007, the 20-year-old singer's agent, William Morris Agency's Kirk Sommer, believes that number will significantly increase. "I think by his second to third trip over, he'll be in large theaters and such," Sommer says. With buzz stirring across the pond, Live Nation's Rich Best calls Nutini the "real deal," and predicts the Scottish singer/songwriter will be playing "legitimate theaters" in eight to 12 months. After arriving in America, Nutini has TV performances lined up on "Today" and "Late Night With Conan O'Brien." Nutini has already seen success overseas with sold-out concerts throughout Europe. "These Streets," which debuted at No. 3 on the U.K. charts, has sold 500,000 units, according to his label. "We're in a nice spot where we don't have to bullshit anyone," Luba says. "If we just let people find out about it organically, it will be OK."

Label: Drag City
Agent: Ali Giampino, the Billions Corp.

Armed onstage with a seven-foot harp, a six-piece backup band and a microphone, indie-blog darling Joanna Newsom recently completed her first U.S. headline tour of venues in the 750-capacity range, says Ali Giampino, Newsom's agent at the Billions Corp. Part of the touring strategy for the past two years has been to play the support role for acts like Sufjan Stevens, Devendra Barnhart, Smog, the Incredible String Band and Will Oldham. "All of those support tours she did was a smart way to get recognized and build a fan base before doing a headlining tour," Giampino says, noting that appearances at the Sasquatch (George, Wash.) and Bonnaroo (Manchester, Tenn.) festivals provided greater exposure. House of Blues Concerts' Zacks says Newsom's set at Sasquatch in 2005 was "one of the most talked about performances of that year." On Dec. 4, two months after the release of her album, "Ys," Newsom played to a sold-out crowd at Seattle's 1,100-capacity Showbox, according to Zacks. So where does Newsom go from there? "I think she's well-suited for small theaters -- or big theaters in some markets," Zacks says. In mid-January, Newsom heads to the United Kingdom to play a handful of orchestral concerts. "She's going to see how she likes those," Giampino says, "and if she does, she might try to do a few orchestral shows in the United States -- possibly [one] at the Hollywood Bowl."